Apparatus for a bicycle hub brake

ABSTRACT

A bicycle hub brake component is provided for braking a hub of a wheel mounted on a bicycle frame. The component comprises a brake drum adapted to rotate integrally with the hub, and a brake shoe. The brake drum has a brake face on an inner peripheral surface thereof, and the brake shoe has a contact surface that contacts the brake face of the brake drum to apply a braking force to the brake drum. A grease groove is formed in the brake face of the brake drum, wherein the grease groove is aligned between side edges of the contact surface of the brake shoe.

BACKGROUND OF INVENTION

[0001] The present invention is directed to bicycle brake devices and,more particularly, to bicycle brake devices that are used to brake a hubof a bicycle wheel.

[0002] Bicycle braking devices currently available include rim brakingdevices and hub braking devices. Rim braking devices include cantileverbrakes or caliper brakes that brake the rim of the wheel. Hub brakingdevices brake the wheel hub, and they include drum brakes, band brakes,roller brakes and the like. A hub brake brakes the hub of the wheel, soit is able to provide braking even if the wheel rim is warped.

[0003] A drum brake such as a roller brake effects braking by means offriction created when a brake shoe contacts the inside peripheral face(braking surface) of a tubular brake drum that rotates in unison withthe wheel hub. In a roller brake, a cam displaces rollers spaced apartin the circumferential direction diametrically outward in order to movea brake shoe against the inner peripheral face of the brake drum. Theinterior of roller brakes is filled with grease, particularly in thearea between the contact surface of the brake shoe and the brakingsurface. The grease can control the heat produced during braking toimprove durability and produce more consistent braking performance. Thegrease also allows the rollers to move smoothly.

[0004] Inconsistent braking performance and braking malfunctions canoccur when such conventional hub brake devices run out of grease. Theefficient supply of grease between the braking surface and the contactsurface is therefore desirable to minimize such malfunctions.

SUMMARY OF THE INVENTION

[0005] The present invention is directed to inventive features of abicycle braking device. In one embodiment, a bicycle hub brake componentis provided for braking a hub of a wheel mounted on a bicycle frame. Thecomponent comprises a brake drum adapted to rotate integrally with thehub, and a brake shoe. The brake drum has a brake face on an innerperipheral surface thereof, and the brake shoe has a contact surfacethat contacts the brake face of the brake drum to apply a braking forceto the brake drum. A grease groove is formed in the brake face of thebrake drum, wherein the grease groove is aligned between side edges ofthe contact surface of the brake shoe.

[0006] Additional inventive features will become apparent from thedescription below, and such features alone or in combination with theabove features may form the basis of further inventions as recited inthe claims and their equivalents.

BRIEF DESCRIPTION OF DRAWINGS

[0007]FIG. 1 is a side view of a particular embodiment of a bicycle thatincludes braking components described herein;

[0008]FIG. 2 is a schematic illustration of a particular embodiment of abrake system for the bicycle;

[0009]FIG. 3 is a side view of a particular embodiment of a front brakedevice;

[0010]FIG. 4 is a front view of the front brake device;

[0011]FIG. 5 is a side view of the front brake device with the coverremoved;

[0012]FIG. 6 is an enlarged partial cross-sectional view of the frontbrake device;

[0013]FIG. 7(A) is a partial cross-sectional view of a particularembodiment of a cooling disk press fit to a brake drum;

[0014]FIG. 7(B) is a partial cross-sectional view of the cooling diskcrimped and caulked to the brake drum;

[0015]FIG. 8 is an exploded view of a particular embodiment of thebicycle brake device;

[0016]FIG. 9 is a perspective view of a particular embodiment of aretaining member;

[0017]FIG. 10 is a cross sectional view of the retaining member of FIG.9 in a crimped condition;

[0018]FIG. 11 is a perspective view of another embodiment of a retainingmember;

[0019]FIG. 12 is a cross sectional view of the retaining member of FIG.11 in a crimped condition;

[0020]FIG. 13 is a perspective view of particular embodiments of aninsert member and a detaining portion of a bracket body;

[0021]FIG. 14 is a side cross sectional view of the insert member andthe bracket body prior to mounting the insert member;

[0022]FIG. 15 is a side cross sectional view of the insert member andthe bracket body after mounting the insert member;

[0023]FIG. 16 is a side view of a particular embodiment of a brake shoeassembly;

[0024]FIG. 17 is a plan view of a portion of the brake shoe assembly;

[0025]FIG. 18 is an enlarged view of a distal end of a brake shoe;

[0026]FIG. 19 is an exploded view of a particular embodiment of mountingportions of the actuating arm;

[0027]FIG. 20 is a partial cross sectional view of the brake device in abrake released state;

[0028]FIG. 21 is a partial cross sectional view of the brake device in abrake activated state;

[0029] FIGS. 22(A)-22(C) illustrate embodiments of projecting portionsof a spring member;

[0030]FIG. 23 is a plan view of an another embodiment of a brake shoe;and

[0031]FIG. 24 is a plan view of another embodiment of a brake shoe.

DETAILED DESCRIPTION

[0032]FIG. 1 is a side view of a particular embodiment of a bicycle thatincludes braking components described herein. In this embodiment, thebicycle comprises a frame 1 that has a frame body 2 and a front fork 3;a handlebar portion 4 comprising a handle stem 10 fastened to the top offront fork 3 and a handlebar 11 fastened to handle stem 10 for steering;a saddle 9 for sitting; a front wheel 6; a rear wheel 7; a brake system8 for braking front wheel 6 and rear wheel 7; and a drive section 5 fortransmitting rotation of pedals 5 a to rear wheel 7.

[0033] Front wheel 6 and rear wheel 7 have front and rear hubs 6 a (FIG.4, wherein only the front hub 6 a is shown), each having a hub spindle15 a (FIG. 6), front and rear rims 6 b, 7 b (FIG. 1) disposed at theoutside periphery of hubs 6 b, tires 6 c, 7 c attached to front and rearrims 6 b, 7 b, and spokes 6 d, 7 d connecting the hubs 6 a with therespective rims 6 b, 7 b. As shown in FIG. 6, hub 6 a hub spindle 15 ais nonrotatably mounted on front fork 3 of frame 1, and a hub shell 15 bis rotatably supported on hub spindle 15 a. Front hub 6 a has a quickrelease lever 6 e (FIG. 1) to provide a quick release hub that is easyto detach. The quick release mechanism is known and described, forexample, in the 1993 Japanese Industrial Standard (JIS) Bicycle Edition,p. 276, published by Jitensha Sangyo Shinko Kyokai. Thus, a detaileddescription of the quick release mechanism will not be provided here. Inthis embodiment, the hubs 6 a are fastened to the front fork 3 and chainstay 2 a with an ordinary hexagon cap nut 45.

[0034] As shown in FIG. 2, brake system 8 has front and rear brakelevers 12 f, 12 r, brake devices 13 f, 13 r actuated by front and rearbrake levers 12 f, 12 r, and front and rear brake cables 14 f, 14 rrespectively linking the front and rear brake levers 12 f, 12 r with thefront and rear brake devices 13 f, 13 r. Brake cables 14 f, 14 r haveinner cables 16 f, 16 r, the two ends of which are linked to front andrear brake levers 12 f, 12 r and the front and rear brake devices 13 f,13 r. Brake cables 14 f, 14 r also have outer cables 17 f, 17 rsheathing the inner cables 16 f, 16 r. The front brake lever 12 f ismounted to the inside of a grip 18 a mounted on the left end ofhandlebar 11, and the rear brake lever 12 r is mounted to the inside ofa grip 18 b mounted on the right end of handlebar 11. Brake levers 12 f,12 r are identical components disposed in a mirror image relationship.Each brake lever 12 f, 12 r has a lever bracket 20 mounted on handlebar11, a lever member 21 pivotably supported on a pivot shaft 20 a on leverbracket 20, and an outer detaining portion 22 screwed onto lever bracket20. Each lever bracket 20 has a mounting portion 20 b and a femalethreaded portion 20 c, wherein mounting portion 20 b is detachablymountable to handlebar 11, and outer detaining portion 22 is threadedinto female threaded portion 20 c. Inner cables 16 f, 16 r passesthrough their respective outer detaining portions 22 and are detained bycorresponding inner detaining portions 21 a mounted to each lever member21. Lever member 21 is biased towards the brake release position by abiasing member (not shown).

[0035] In this embodiment, the front and rear brake devices 13 f, 13 rare roller brake devices. Brake devices 13 f, 13 r function to brake thehub 6 a of front wheel 6 and rear wheel 7, respectively. As shown inFIGS. 2, 3, and 8, brake devices 13 f, 13 r have fastening brackets 30f, 30 r for nonrotatably fastening brake devices 13 f, 13 r to the frontfork 3 or chain stay 2 a of the bicycle; brake bodies 32 f, 32 r; andbrake actuating portions 33 f, 33 r for actuating the brake bodies 32 f,32 r. Each fastening bracket 30 f, 30 r has a bracket body 34 with afirst face and a second face produced, for example, by press forming asheet of steel, and a cover member 35 securely fitting onto bracket body34 for covering the second face of bracket body 34. Cover member 35 isformed by press forming a thin metal sheet, has a baked-on finish on itssurface, and has indicia such as a model number imprinted thereon.Bracket body 34 has a basal portion 34 a (FIG. 8) through which hubspindle 15 is passed, a tapering arm portion 34 b that extendssubstantially diametrically from basal portion 34 a, and a detainingportion 34 c formed at the distal end of arm portion 34 b with asubstantially equal width plate configuration. As shown in FIG. 6, thebasal portion 34 a of bracket body 34 is fastened to hub spindle 15 a bymeans of the hexagonal cap nut 45 screwed onto one end of hub spindle 15a. On basal portion 34 a, except in the arm portion 34 b, is formed atubular portion 34 d of very short length. This tubular portion 34 dforms a member mounting portion 38 comprising a pair of mounting holes38 a, 38 b for mounting first detaining members 36, 37 that prevent thebrake drum 40 from coming off in a manner described below.

[0036] As shown in FIGS. 1 and 13-15, the detaining portion 34 c ofbracket body 34 is fastened to a bracket fastening member 25 f, 25 r.The detaining portion 34 c of the front bracket body 34 is detaineddetachably, by a one-touch operation, by bracket fastening member 25 fin order to facilitate replacement of front wheel 6. On a first face ofthe front detaining portion 34 c (the left face in FIG. 14), there isformed a recess 34 e recessed inwardly and extending in the mountingdirection. Recess 34 e is produced by a press forming process, forexample, and projects towards a second face of front detaining portion34 c (the right face in FIG. 14). Bracket fastening member 25 f issupplied together with the front brake device 13 f by the brakemanufacturer, and it is welded to the front fork 3 of the bicycle frame1. Bracket fastening member 25 f has a detaining space 25 a fordetaining detaining portion 34 c when the latter is inserted therein.The two side walls 25 b of detaining space 25 a are bowed slightlyinward so that detaining space 25 a has greater width at its mouth (thedistance between the side walls 25 b at the lower end in FIG. 15) forinsertion of detaining portion 34 c than it does in its medial portionsituated further inward. Since the width at the mouth is greater thanthe width further inward, detaining portion 34 c can be detainedregardless of differences in configuration of the front fork 3 of thebicycle.

[0037] An insert member 19 produced, for example, by bending a thinsheet of stainless steel for ease of manufacture, durability andcorrosion resistance, is mounted on the front detaining portion 34 c.Insert member 19 is arranged such that it is situated within detainingspace 25 a when mounted on detaining portion 34 c. Insert member 19 hasfirst and second contact portions 19 a, 19 b and a third contact portion19 c. First and second contact portions 19 a, 19 b mount onto thedetaining portion 34 c from the distal edge thereof, and third contactportion 19 c contacts a side of detaining portion 34 c due to being bentout from the first contact portion 19 a which is juxtaposed to a firstface of detaining portion 34 c. The first and second contact portions 19a, 19 b are bent towards the two faces of detaining portion 34 c so thatthe bent portions are situated at the distal edge thereof. A convexportion 19 d is formed on first contact portion 19 a for mating withrecessed portion 34 e of detaining portion 34 c. By engaging convexportion 19 d within recessed portion 34 e, insert member 19 may bemounted at a desired location on detaining portion 34 c when insertmember 19 is mounted in fastening member 25 f. Since the second face ofdetaining portion 34 c projects outwardly (to the right in FIG. 14), thesecond contact portion 19 b of insert member 19 situated at this secondface is bent diagonally. It is therefore easier to fill the gap of thedetaining space 25 a of bracket fastening member 25 f for reducing thechatter of the brake device 13 f in the axial direction when mounted onthe front fork 3. Furthermore, third contact portion 19 c is bentdiagonally along detaining space 25 a as shown in FIG. 15. Accordingly,it is easy to fill in the convex gap of the detaining space 25 a ofbracket fastening member 25 f for reducing chatter in the hub rotationdirection.

[0038] As shown in FIGS. 2 and 3, bracket fastening members 25 f, 25 rand fastening brackets 30 f, 30 r, respectively, have mounted thereonouter mounting portions 31 f, 31 r for detaining the outer cables 17 f,17 r. For example, outer mounting portion 31 f may be screwed to thefront bracket fastening member 25 f. Outer mounting portion 31 f has anouter detaining portion 31 a and an outer fastening portion 31 b. Outerdetaining portion 31 a is provided for detaining outer cable 17 f, andouter fastening portion 31 b is provided for fastening outer detainingportion 31 a in such a way that the detaining position of outerdetaining portion 31 a in the cable axis direction is adjustable bymeans of a screw. Brake play (i.e. the gap between the brake drum andthe brake shoe) can be adjusted by adjusting this axial position. Sinceouter mounting portions 31 f are mounted to the frame, there is no needto attach or detach the outer cable when attaching or detaching thewheel.

[0039] Since brake bodies 32 f, 32 r are of substantially identicalstructure, only the front brake body 32 f will be described. As shown inFIG. 6, front brake body 32 f has a brake drum 40 and a brake shoe 41.Brake drum 40 has a cylindrical drum body 43 that rotates integrallywith the hub shell 15 b through a left pocket 15 c. Drum body 43 is astainless steel alloy member having a bowl configuration with a bottomportion 50 and a peripheral portion 51 formed at the outside peripheryof bottom portion 50. A contoured (splined) portion 50 b is formed onthe inside peripheral surface of an opening 50 a in bottom portion 50,wherein the splined portion 50 b meshes with a complementary splinedportion formed on the outer peripheral surface of left pocket 15 c. As aresult, drum body 43 is nonrotatably mounted relative to hub shell 15 b.

[0040] A circular brake face 51 a is formed on the inside peripheralface of peripheral portion 51, wherein brake shoe 41 is capable ofcontacting with and releasing from brake face 51 a to provide a brakingforce to brake drum 40. Brake face 51 a is produced by recessing theaxial center portion of peripheral portion 51 in an isoscelestrapezoidal shape whose cross section constricts in width goingoutwardly in the diametrical direction. As shown in FIGS. 7(A) and 7(B),the angle Î± at which the two sides of brake face 51 a intersect rangesfrom 15Â° to 150Â°, preferably 80Â° to 100Â°. Brake face 51 a has adiametrically outwardly extending annular grease filled recess 54 packedwith grease. Grease filled recess 54 has a first groove 54 a, formed inthe most deeply recessed portion of brake face 51 a so that grease tendsto flow into first groove 54 a through centrifugal force during riding,and a pair of second grooves 54 b situated on brake face 51 a atopposite sides of first groove 54 a to increase the amount of greasethat may be supplied. Grease filled recess 54 is packed with grease atthe time of assembly.

[0041] A cooling disk 44 made of aluminum alloy is thermally coupled tothe outer peripheral surface of drum body 43. Cooling disk 44 has atubular portion 44 b and a disk portion 44 c, wherein disk portion 44 cextends diametrically outward from tubular portion 44 b. A plurality ofradially extending cooling fins 44 a (FIG. 4) are formed on the inside(right side) face of cooling disk 44 for dissipating heat from hub body43. Such dissipation is enhanced by the increased surface area as wellas the increased contact with air when the wheel is spinning.

[0042] As shown in FIGS. 7(A) and 7(B), a knurled portion 51 b is formedon the outside peripheral face of peripheral portion 51 by means of aknurling process in order to prevent rotation of cooling disk 44relative to hub body 43 when cooling disk 44 is mounted to hub body 43.The outer peripheral surface of peripheral portion 51 also has formedthereon a first tapered face 51 c and a second tapered face 51 dsituated on opposite sides of knurled portion 51 b, wherein taperedfaces 51 c, 51 d taper downwardly in the diametrical direction. Firsttapered face 51 c is provided for axially detaining the cooling disk 44to drum body 43, and second tapered face 51 d is provided for fasteningcooling disk 44 to hub body 43 by crimping and/or caulking. A flat outerperipheral press fitting face 51 e is formed between first tapered face51 c and knurled portion 51 b. Cooling disk 44 is press fit onto theentire circumference of press fitting face 51 e and the knurled portion51 b so that grease packed into the brake drum 40 can be prevented fromflowing through the side of hub 6 a.

[0043] During the fabrication stage, a cylindrical caulk fasteningportion 44 d is formed on a first end of tubular portion 44 b (the rightend in FIG. 7(A)). To fasten the cooling disk 44 to the drum body 43during the assembly stage, the tubular portion 44 b is initially pressfit onto the outside peripheral face of drum body 43 as shown in FIG.7(A). A shaving reservoir portion 58 is formed on the inside peripheralsurface of tubular portion 44 b for holding shavings produced by knurledportion 51 b during the press fitting process. Thereafter the caulkfastening portion 44 d is bent diametrically inward towards the secondtapered face 51 d of the drum body 43 as shown in FIG. 7(B) using aroller or some other suitable jig. By press fitting the cooling disk 44and caulking it onto the drum body 43 in this manner, the cooling disk44 is securely fastened onto the drum body 43, especially in the axialdirection. The larger contact area produced by the tapered faces alsoimproves cooling efficiency. The press fitting/caulking operation doesnot require application of heat, and it can be performed at the samelocation. Thus, heat-induced discoloration and deformation is avoided,the labor entailed in the production process is reduced, and the coolingdisk 44 is fastened to the drum body 43 in a simple and inexpensivemanner.

[0044] The other end of the tubular portion 44 b of cooling disk 44 (theleft end in FIG. 7) has a diametrically outwardly projecting annularconvex portion 44 e for preventing the brake drum 40 from coming off ofthe fastening bracket 30 when attaching or detaching the brake device 13f. More specifically, two kinds of first retaining members 36, 37 (FIGS.8-12) are detachably mounted on member mounting portion 38 of tubularportion 34 d of bracket body 34, and a second retaining member 39 isproduced by bending cover member 35 diametrically inwardly. Firstretaining members 36, 37 and second retaining portion 39 are received inthe annular groove formed between annular convex portion 44 e and diskportion 44 c of cooling disk 44

[0045] As shown in FIGS. 9 and 10, first retaining member 36 is a bentplate member made of stainless steel alloy. First retaining member 36has a retaining projection 36 a that is adapted to be fitted axiallyinwardly of annular convex portion 44 e, a mounting portion 36 bproduced by bending retaining projection 36 a so as to be situatedagainst the inner peripheral face of tubular portion 34 d, and bentfastening portions 36 c produced by cutting the two ends of mountingportion 36 b and bending them in the upward direction as shown in FIG.9. These bent fastening portions 36 c are inserted into mounting holes38 a, 38 b from the inner peripheral side of tubular portion 34 d, andtheir distal ends are bent over to mount the first retaining member 36onto the inside peripheral face of tubular portion 34 d as shown in FIG.10.

[0046] As shown in FIGS. 11 and 12, first retaining member 37 is a bentplate member made of stainless steel alloy. First retaining member 37has retaining projection 37 a that is adapted to be fitted axiallyinwardly of annular convex portion 44 e of cooling disk 44 a mountingportion 37 b produced by bending retaining projection 37 a so as to besituated against the outer peripheral face of tubular portion 34 d, andelastic fastening portions 37 c produced by cutting the two ends ofmounting portion 37 b and bending them in the downward direction in aU-shape as shown in FIG. 11. These elastic fastening portions 37 c areinserted into mounting holes 38 a, 38 b from the outside peripheral sideof tubular portion 34 d. Once elastic fastening portions 37 c havepassed through mounting holes 38 a, 38 b, they spread out due toelasticity and are elastically detained on tubular portion 34 d, therebyfastening the first retaining member 37 to the outside peripheral faceof tubular portion 3 Although the tips of the elastic fastening portions37 c are shown touching the inner peripheral surface of tubular portion34 d, they may instead touch the side walls of mounting holes 38 a, 38b. 4 d. First retaining member 37 may be removed by prying mountingportion 37 b.

[0047] As shown in FIG. 8, the second retaining member 39 is formed bybending the cover member 35 inwardly. Second retaining member 39 also isprovided for preventing the brake drum 40 from coming off, as well as todetain the cover member 35 on the bracket body 34. Cover member 35 isfastened to tubular portion 34 d by means of elastic detenting.Providing a second retaining member 39 on cover member 35 allows thenumber of retaining members 36,37 to be reduced as well as reducingmanufacturing costs and the number of steps required to attach thebracket body 34 to brake drum 40. Cover member 35 has a bulging portion35 a formed so as to cover the outside peripheral side of firstretaining portion 37, thus making the first retaining member 37 (whichis easier to detach than the first retaining member 36 because the firstretaining member 36 was fastened to tubular portion 34 d by bending)harder to remove.

[0048] By preventing the brake drum 40 from coming off by means of firstretaining members 36, 37, which are detachable from the tubular portion34 d, and the second retaining member formed on cover member 35 r,damage to fastening bracket and cover member 3530 f is prevented whenfirst retaining members 36,37 and second retaining member 39 areattached or detached. The brake drum 40 thus can be retained withoutbreaking fastening bracket and cover member 3530 f, when brake device 13r is repeatedly disassembled and reassembled.

[0049] In this embodiment, as shown in FIGS. 16 and 17, brake shoe 41consists of a ring-shaped member divided into three segments in thecircumferential direction. A contact face 41 a is formed on the outerperipheral surface of each segment of brake shoe 41 for contacting thebrake face 51 a of drum body 43 during braking. Each contact face 41 ahas a cross sectional shape in the form of an isosceles trapezoidprojecting convexly in the radially outward direction so as to contactbrake face 51 a. The angle Î² of intersection of the two sides ofcontact face 41 a is equal to or greater than the intersect angle Î± ofbrake face 51 a. As shown in FIG. 18, sloping faces 41 e are formed atthe two end portions of the contact faces 41 a such that an acute angleÎ³ is formed with respect to a tangent line 81 at the location ofcontact of a sloping face 41 e with an arbitrary arc 80 on brake face 51a. By providing such sloping faces 41 e, grease delivered to the slopingfaces during rotation of the brake drum 40 can be supplied smoothly tothe brake face 51 a. Thus, grease depletion is not likely to occur atthe brake face 51 a. In the center of contact face 41 a is formed anannular housing recess 41 b in which a first spring member 53 ismounted. Housing recess 41 b is formed so as to be juxtaposed to firstgroove 54 a of grease filled recess 54 in drum body 43.

[0050] Three diametrically outwardly recessed rotation stop portions 41c extending a predetermined length in the rotation direction is formedon the inside peripheral surface of brake shoe 41. Three detainingprojections 34 f (FIGS. 6 and 8) formed on bracket body 34 of fasteningbracket 30 f fit within these rotation stop portions 41 c, thuspreventing rotation of the segmented brake shoe 41 relative to bracketbody 34. Of course, brake shoe 41 will rotate slightly due to playbetween detaining projections 34 f and rotation stop portions 41 c.

[0051] The first spring member 53 mounted in housing recess 41 b is anannular spring member formed by bending elastic wire material into acircle. Such a configuration makes it easy to bias each segment of brakeshoe 41 inwardly towards a position away from the brake drum 40 (i.e.,diametrically inward). A first end of the first spring member 53 has aprojecting portion 53 a that is bent to project diametrically outwardly.In this embodiment, projecting portion 53 a projects outwardlyapproximately 0.4 mm-2.0 mm from the inside peripheral portion. As aresult, when brake shoe 41 contacts the brake drum 40 during braking,the distal end of projecting portion 53 a tends to be situated withinfirst groove 54 a of grease filled recess 54. During brake release, whenthe brake shoe 41 comes away from the brake drum 40, projecting portion53 a tends to be situated diametrically inward from first groove 54 agroove. In this way, during braking (and possibly only during braking),projecting portion 53 a can rake out the grease packed into first groove54 a towards the brake face 51 a. The size of projecting portion 53 aalso ends to require no major change in the usual assembly machinery,assembly process, tools, or the like.

[0052] Brake actuating portions 33 f, 33 r are substantially identicalin construction despite their difference in shape, so only the frontbrake actuating portion 33 f will be described here. The front brakeactuating portion 33 f is rotatably disposed on fastening bracket 30,and it is used to push the segments of brake shoe 41 towards the brakedrum 40. As shown in FIGS. 8 and 19, the front brake actuating portion33 f has an actuating arm 60 adapted to be mounted on the bracket body34 of fastening bracket 30 f so that actuating arm 60 rotates round thehub spindle 15 a; a cam member 61 that rotates in unison with theactuating arm 60; a plurality of rollers 62 (e.g., six) disposed betweenand contacting cam member 61 and brake shoe 41; and a roller case 63 forholding the rollers 62 spaced apart from each other in the rotationdirection.

[0053] Actuating arm 60 is fabricated from a metal plate. An innermounting portion 64 is detachably mounted to the distal end of actuatingarm 60 for detaining the distal end of inner cable 16 f of brake cable14 f. Actuating arm 60, which is actuated by means of inner cable 16 fvia inner mounting portion 64, is linked to the brake lever 12 f mountedon the handlebar portion 4 of the bicycle. The basal end of actuatingarm 60 is bent and has a mating hole 60 a (FIG. 8) for mating with theoutside peripheral face of cam portion 61. Actuating arm 60 rotatesbetween a brake released position (shown in FIG. 20) and a brakingposition (shown in FIG. 21) Actuating arm 60 is biased toward the brakereleased position by a second spring member 70 in the form of a torsioncoil spring. One end of spring member 70 is detained by bracket body 34,and the other end of spring member 70 is detained in a detaining hole 60b formed in the distal end of actuating arm 60. Second spring member 70is covered by cover member 35.

[0054] As shown in FIG. 19, a mounting slot 65 is formed on the distalend of actuating arm 60 for detachably mounting the inner mountingportion 64. Mounting slot 65 proceeds up from the bottom of the distalend of actuating arm 60, bends towards the rotational axis of theactuating 60, and then bends diagonally downward. Slot 65 includes aconstricted portion 65 a that is disposed at the bent portion, whereinconstricted portion 65 a is narrower in width than other portions. Inthis embodiment, constricted portion 65 a has a width d2 of 5.4 mm, anda back end/front end width d1 of 5.9 mm. An attachment/detachmentoperation portion 60 c used for attaching or detaching inner mountingportion 64 is formed at the bottom of the distal end of actuating arm60. Attachment/detachment operation portion 60 c also facilitatesrotation of actuating arm 60, of necessary, when attaching and detachinginner mounting portion 64 from actuating arm 60.

[0055] Inner mounting portion 64 has a plate-shaped arm body 66 formedby bending metal sheet material, a retaining portion 67 disposed at thebasal end of arm body 66 (the bottom end in FIG. 19), and a cabledetaining portion 68 screwed to the distal end of arm body 66. The basalend of arm body 66 is bent into a “U” configuration to form a bracketportion 66 a for supporting retaining portion 67. Retaining portion 67is detachably and rotatably mounted in mounting slot 65 of actuating arm60, and cable detaining portion 68 is provided for detaining inner cable16 f. An attachment/detachment operation portion 66 b that aligns withcable detaining portion 68 is formed at the distal end of arm body 66.Attachment/detachment operation portion 66 b extends away from cabledetaining portion 68 and then bends sideways. Inner cable 16 f thus maybe removed as a unit with inner mounting portion 64, and it is notnecessary to adjust the brake play every time the wheel is replaced.Also, since inner mounting portion 64 is a large member, it may beeasily removed with one hand.

[0056] Retaining portion 67 has a flanged retaining shaft 67 a fixed tobracket portion 66 a, a spring pin 67 b mounted on retaining shaft 67 a,and a washer 67 c disposed such that it contacts spring pin 67 b. Springpin 67 b has an axially extending slit formed in its outside periphery,and it may be formed by winding elastic sheet material. Spring pin 67 bhas an outside diameter greater than constricted portion 65 a ofmounting slot 65, a width smaller than mounting slot 65 with theexception of constricted portion 65 a, and an inside diameter greaterthan the outside diameter of retaining shaft 67. When spring pin 67 b isinserted into the mounting slot 65 to mount the inner mounting portion64 on actuating arm 60, spring pin 67 b inserts smoothly into theentrance of mounting slot 65, is diametrically constricted as it passesthrough the constricted portion 65 a of mounting slot 65, and thenexpands to its original shape once it has passed through the constrictedportion 65 a. As a result, it will not return back through theconstricted portion 65 a during normal operation. However, when holdingthe two attachment/detachment operation portions 60 c, 66 b, theretaining portion 67 moves easily out of the mounting slot, and theinner mounting portion 64 can be easily detached from the actuating arm60.

[0057] Cam member 61 is nonrotatably fixed to actuating arm 60 so thatit rotates in response to rotation of actuating arm 60. As shown inFIGS. 8, 20 and 21, cam member 61 may be a thick-walled tubular memberfabricated of steel. A plurality of cam portions 61 c are formed on theouter peripheral face of cam member 61. Each cam portion 61 c has asloping cam face 61 a and a recessed portion 61 b. In this embodiment,the distance in the diametrical direction of each cam face 61 aincreases gradually in the clockwise direction in FIG. 20, and therecessed portions 61 b are recessed below adjacent pairs of sloping camfaces 61 a.

[0058] Roller abutting faces 41 d (FIG. 16) that project diametricallyinwardly are disposed at the inside peripheral surface at the two endsof each segment of brake shoe 41. Rollers 62 are mounted between theoutside peripheral surface of cam member 61 and the roller abutting face41 d of brake shoe 41. Rollers 62 are used to push against brake shoe 41in response to rotation of cam member 61. Rollers 62 are mounted in aroller case 63 in such a manner that they are spaced apart in acircumferential direction while being capable of movement in adiametrical direction in response to rotation of cam member 61. Morespecifically, a plurality of retaining projections 63 a (e.g., six) areformed in roller case 63. The retaining projections 63 a arecircumferentially spaced apart and project outwardly in the hub axialdirection for retaining the rollers 62. Roller case 63 is nonrotatablydetained to bracket body 34 by means of a retaining projection 63 b thatprojects axially further than the other retaining projections 63 a. Asshown in FIGS. 5, 6, and 8, a slot 34 g that is elongated in therotation direction is formed in bracket body 34 for mating with thisretaining projection 63 b. A third spring member 72 is mounted betweenretaining projection 63 b and bracket body 34 for biasing the rollercase 63 in the clockwise direction in FIG. 20. Thus, the rollers 62 aresubstantially fixed relative to bracket body 34. Grease is packed withinthe roller case 63 around the rollers 62 in the same manner as for brakeface 51 a so that rollers 62 can move smoothly in the diametricaldirection in response to rotation of cam member 61. The use of rollersalso helps to minimize evaporation of grease and the fluctuation inbraking performance due to a rise in brake temperature.

[0059] The operation of brake devices 13 f, 13 r will be described withreference to the front brake device 13 f described above. With the brakecables 14 f, 14 r set up, the inner cables 16 f, 16 r are under tension,and play between brake shoe 41 and brake drum 40 in the absence ofoperation of brake levers 12 f, 12 r may be adjusted by means of theouter detaining portion 22 mounted on brake levers 12 f, 12 r or theouter mounting portions 31 f, 31 r mounted on brake device 13 f, 13 r.In this state, squeezing the front brake lever 12 f causes the innercable 16 f to pull in opposition to the biasing force of the secondspring member 70, so that the actuating arm 60 rotates from the brakerelease position shown in FIG. 20 to the braking position shown in FIG.21.

[0060] When actuating arm 60 rotates to the braking position, cam member61 rotates integrally therewith, and the rollers 62 ride up over thesloped cam faces 61 a. As a result, rollers 62 are displaceddiametrically outwardly and press the contact faces 41 a of brake shoe41 against the brake face 51 a of brake drum 40 in opposition to thebiasing force of the first spring member 53. This initially produces abraking force proportional to the pushing force on brake shoe 41. Sincebrake drum 40 is rotating in the counterclockwise direction of FIG. 21at this time, brake shoe 41 also turns slightly counterclockwise, androller case 63 rotates slightly in the same direction via rollers 62.This causes rollers 62 to be displaced further diametrically outwardlyand produces an increased braking force. Since the brake face 51 a isrecessed in a trapezoidal configuration and the contact face 41 aprojects outwardly in a trapezoidal configuration, the frictionalcontact force between the friction faces increases through a wedgingaction. Since the contact area is larger than it would be between flatperipheral surfaces, the frictional force is larger and produces a highbraking torque in a unit of compact size. On the other hand, the heatgenerated per unit of surface area is held to a lower level. Thus, highbrake temperature is unlikely to occur, and a fluctuation in brakingforce due to a rise in brake temperature can be reduced.

[0061] When the hand is released from front brake lever 12 f, actuatingarm 60 returns to the brake released position in accordance with thebiasing force of the second spring member 70. Since cam member 61rotates integrally with actuating arm 60, rollers 62 ride down thesloped cam faces 61 a, and the brake shoe 41 moves diametricallyinwardly in accordance with the biasing force of the first spring member53. At this time, the roller case 63 rotates in the clockwise directionin accordance with the biasing force of the third spring member 72, andthe braking force stops.

[0062] When assembling the brake drum 40, the drum body 43 and coolingdisk 44 forms are fabricated by a process such as die casting orforging, and the forms are then finished to the desired dimensions bymachining processes. At that time, cooling disk 44 has a shape like thatshown in FIG. 7(a), with caulk fastening portion 44 d having the form ofa cylinder. Cooling disk 44 then is press fit onto the outsideperipheral surface of drum body 43. After being press fit, caulkfastening portion 44 d is bent diametrically inward towards the caulkingface 51 d to effect caulking of the cooling disk 44 to the drum body 43using a roller or the like.

[0063] Then, two segments of the brake shoes 41 and the first springmember 53 are assembled and mounted inside the drum body, and theremaining segment of brake shoe 41 is attached so that the first springmember 53 enters the housing recess 41 b. The interior may be packedwith ample grease at this time. When the mounting of brake shoe 41 iscompleted, the segments of brake shoe 41 are pushed against brake face51 a, the rollers 62 are mounted in the roller case 63, and both areinserted diametrically inwardly of brake shoe 41. The interior may befurther coated with ample grease at this time.

[0064] Then, the cam member 61 having the actuating arm 60 fastenedthereto is inserted diametrically inwardly of rollers Retaining member36 is attached to tubular portion 34 d of bracket body 34, bracket body34 is assembled to brake drum 40 so that retaining member 36 engagesannular protrusion 44 e on brake drum 40, and retaining member 37 isattached to tubular portion 34 d of bracket body 34 from the outside toengage annular protrusion 44 e. The two kinds of retaining members 36,37 thus prevent brake drum 40 from coming off. Finally, the third springmember 72 is hooked between bracket body 34 and detaining projection 63b of roller case 63, and the cover member 35 is attached to complete theassembly procedure. The disassembly procedure is the reverse of theabove. Thus, fastening bracket 30 f and brake drum 40 may be removed asa unit from the frame, and then brake drum 40 may be removed fromfastening bracket 30 f by removing cover 35, prying retaining member 37from tubular portion 34 d of bracket body 34, and tilting bracket body34 to disengage retaining member 36 from the annular protrusion 44 e ofbrake drum 40.ove.

[0065] When assembling the front wheel 6 having the brake device 13 fmounted thereon onto the front fork 3, the insert member 19 mounted onthe detaining portion 34 c of bracket body 34 of brake device 13 f ispushed into bracket fastening portion 25 f, and the hub spindle 15 a ofhub 6 a is mounted on front fork 3. The hexagonal cap nuts 45 are theninstalled on both ends of hub spindle 15 a and tightened to theappropriate level of torque to complete mounting of the front wheel 6.Once the front wheel 6 has been mounted, the inner mounting portion 64is mounted on the actuating arm 60 by inserting the spring pin 67 b intomounting slot 65

[0066] The front wheel 6 may be removed by substantially reversing theabove procedure. However, when removing the inner mounting portion 64,the attachment/detachment operation portion 60 c is held with one hand,the attachment/detachment portion 66 b is held with the other hand, andthe retaining portion 67 of the inner mounting portion 64 is withdrawnfrom the mounting slot 65. At this time, a small amount of force isneeded to constrict the diameter of the spring pin 67 b as it passesthrough the constricted portion 65 a, but the part removes easily oncepast the constricted portion. Since the inner mounting portion 64 is nota small part, unlike conventional ones, it is easily grasped and easy toattach and detach.

[0067] While the above is a description of various embodiments ofinventive features, further modifications may be employed withoutdeparting from the spirit and scope of the present invention. Forexample, a roller brake for braking the wheel hub was described, but thehub brake device is not limited thereto. The inventive features may beapplied to a band brake or drum brake for braking the hub. The brakeface 51 a and contact face 41 a in the described embodiment have atrapezoidal configuration, but the brake face 51 a and contact face 41could be flat faces instead. While the insertion member 19 in thedescribed embodiment was formed form a metal sheet, the insertion membermay be easily molded from a hard synthetic resin. The method forcrimping and/or caulking the cooling disk 44 is not limited to thatdescribed in the preceding embodiment. In the above embodiment, acooling disc was provided with an annular protrusion formed thereon, butthe outer peripheral surface of the drum main unit could have theannular protrusion if no cooling disc is provided. Also, while theretaining members 36,37 were bent and fixed or based on elasticengagement, the method for fixing the first detents is not limited tothese options. An alternative method such as screwing can also could beused. A second detent was provided on the cover member 35 in thedescribed embodiment, but the second detent may also be provided on thebracket main unit 34.

[0068] In the above embodiment, a projecting component 53 a was providedat the end of the annular first spring member 53, as shown in FIG. 22(A), but a projecting component 153 a may be formed in the intermediateportion, not the end, of the first spring member 153 as shown in FIG.22(B). A plurality of projecting components 253 a also may be providedat intervals in the peripheral direction as shown in FIG. 22(C). In thiscase, the projecting components 253 a may be positioned to correspond tothe spacing the brake shoe segments. The shape of the projectingcomponents is not limited to those show in the present drawings.

[0069] In the embodiment described above, inclined surfaces 41 e wereformed at both ends of the contact surface 41 a of the segments of brakeshoe 41 to prevent mistakes during manufacturing and assembly, but aninclined surface 41 e may be formed at just the upstream end (in therotating direction of the brake drum 40) where the grease is more likelyto gather during braking. Because the grease is more likely to collectin areas facing the inner surface of the bottom of the drum body 43,inclined surfaces 141 e, 241 e may be formed inclined towards thoseareas, as shown in FIGS. 23 and 24

[0070] The size, shape, location or orientation of the variouscomponents may be changed as desired. Components that are shown directlyconnected or contacting each other may have intermediate structuresdisposed between them. The functions of one element may be performed bytwo, and vice versa. The structures and functions of one embodiment maybe adopted in another embodiment. It is not necessary for all advantagesto be present in a particular embodiment at the same time. Every featurewhich is unique from the prior art, alone or in combination with otherfeatures, also should be considered a separate description of furtherinventions by the applicant, including the structural and/or functionalconcepts embodied by such feature(s). Thus, the scope of the inventionshould not be limited by the specific structures disclosed or theapparent initial focus or emphasis on a particular structure or feature.

1. A bicycle hub brake component for braking a hub of a wheel mounted ona bicycle frame, wherein the component comprises: a brake drum adaptedto rotate integrally with the hub, wherein the brake drum has a brakeface on an inner peripheral surface thereof, and wherein a grease grooveis formed in the brake face; a brake shoe having a contact surface thatcontacts the brake face of the brake drum to apply a braking force tothe brake drum; and wherein the grease groove is aligned between sideedges of the contact surface of the brake shoe.
 2. The componentaccording to claim 1 further comprising a biasing member that biases thecontact surface of the brake shoe away from the brake face of the brakedrum.
 3. The component according to claim 2 wherein the biasing memberhas a projecting member with a tip that is disposed in the grease grooveduring braking.
 4. The component according to claim 3 wherein the tip ofthe projecting member is disposed substantially outside the greasegroove when the brake shoe is in a brake released position.
 5. Thecomponent according to claim 3 further comprising a receiving groovedisposed in the brake shoe for receiving the biasing member therein. 6.The component according to claim 5 wherein the receiving groove facesthe grease groove.
 7. The component according to claim 6 wherein thebiasing member comprises an elongated member having a bent portionforming the projecting member.
 8. The component according to claim 7wherein the bent portion is disposed at an end of the elongated member.9. The component according to claim 7 wherein the bent portion isdisposed at an intermediate portion of the elongated member.
 10. Thecomponent according to claim 7 wherein the projecting member projectsfrom approximately 1.4 mm to approximately 2.0 mm.
 11. The componentaccording to claim 7 wherein the brake face of the brake drum has across-sectional shape in the form of a recessed trapezoidalconfiguration that constricts in width diametrically outward, andwherein the contact face of the brake shoe has a cross-sectional shapein the form of a convex trapezoidal configuration that constricts inwidth diametrically outward.
 12. The component according to claim 11wherein the grease groove includes a first groove disposed in adiametrically outermost portion of the brake face.
 13. The componentaccording to claim 12 wherein the grease groove includes a pair ofsecond grooves disposed on opposite sides of the first groove.
 14. Thecomponent according to claim 13 wherein the tip of the projecting memberis disposed in the first groove during braking.
 15. The componentaccording to claim 1 wherein the brake shoe has an inclined surfaceformed in an end of the contact surface, wherein the inclined surfaceforms an acute angle with a tangent to the contact surface.
 16. Thecomponent according to claim 15 wherein the inclined surface is formedin an upstream end of the contact surface in a rotation direction of thebrake drum.
 17. The component according to claim 16 wherein the inclinedsurface faces an axial side of the brake drum.
 18. The componentaccording to claim 1 wherein the brake drum comprises: a cylindricaldrum body having the brake face on an inner peripheral surface thereof;and a cooling disk secured to an outer periphery of the drum body.
 19. Abicycle hub brake component for braking a hub of a wheel mounted on abicycle frame, wherein the component comprises: a fixing bracket adaptedto be nonrotatably mounted to the bicycle frame; a brake drum adapted torotate integrally with the hub, wherein the brake drum has a brake faceon an inner peripheral surface thereof, and wherein a grease groove isformed in the brake face; a plurality of brake shoes disposedperipherally around and diametrically inward of the brake face of thebrake drum, wherein the plurality of brake shoes are mounted to besubstantially nonrotatable relative to the fixing bracket, and whereineach brake shoe has a contact surface that contacts the brake face ofthe brake drum to apply a braking force to the brake drum; a biasingmember that biases the plurality of brake shoes diametrically inward,wherein the biasing member has a projecting member with a tip; areceiving groove disposed in the brake shoe for receiving the biasingmember therein; wherein the tip of the projecting member is disposed inthe grease groove during braking, and wherein the tip of the projectingmember is disposed substantially outside the grease groove when thebrake shoe is in a brake released position; an actuating arm that isrotatable around a rotational axis of the hub; a cam member the rotatesintegrally with the actuating arm, wherein the cam member has acontoured outer peripheral surface; and a plurality of rollers disposedbetween the outer peripheral surface of the cam member and the pluralityof brake shoes, wherein the plurality of rollers move diametricallyoutward in response to rotation of the cam member to move the pluralityof brake shoes diametrically outward.
 20. The component according toclaim 19 wherein the biasing member comprises a substantially circularspring wire disposed in the receiving groove, wherein the spring wirehas a bent portion forming the projecting member.
 21. The componentaccording to claim 20 wherein the bent portion is disposed at an end ofthe spring wire.
 22. The component according to claim 20 wherein thebent portion is disposed at an intermediate portion of the spring wire.23. The component according to claim 20 wherein the projecting memberprojects from approximately 1.4 mm to approximately 2.0 mm from an innerperiphery of the spring wire.
 24. The component according to claim 20wherein the brake face of the brake drum has a cross-sectional shape inthe form of a recessed trapezoidal configuration that constricts inwidth diametrically outward, wherein the grease groove includes a firstgroove disposed in a diametrically outermost portion of the brake face,wherein the contact face of the brake shoe has a cross-sectional shapein the form of a convex trapezoidal configuration that constricts inwidth diametrically outward, wherein the receiving recess is disposed ina diametrically outermost portion of the contact face, and wherein thetip of the projecting member is disposed in the first groove duringbraking.
 25. The component according to claim 24 wherein the greasegroove includes a pair of second grooves disposed on opposite sides ofthe first groove.
 26. The component according to claim 19 wherein eachbrake shoe has an inclined surface formed in an upstream end of thecontact surface in a rotation direction of the brake drum, wherein theinclined surface forms an acute angle with a tangent to the contactsurface.
 27. The component according to claim 26 wherein the inclinedsurface faces an axial side of the brake drum.
 28. The componentaccording to claim 19 wherein the brake drum comprises: a cylindricaldrum body having the brake face on an inner peripheral surface thereof;and a cooling disk secured to an outer periphery of the drum body.
 29. Abicycle hub brake component for braking a hub of a wheel mounted on abicycle frame, wherein the component comprises: a brake drum adapted torotate integrally with the hub, wherein the brake drum has a brake faceon an inner peripheral surface thereof; a brake shoe having a contactsurface that contacts the brake face of the brake drum to apply abraking force to the brake drum; and wherein the brake shoe has aninclined surface formed in an upstream end of the contact surface in arotation direction of the brake drum, and wherein the inclined surfaceforms an acute angle with a tangent to the contact surface.
 30. Thecomponent according to claim 29 wherein the inclined surface faces anaxial side of the brake drum.
 31. The component according to claim 29further comprising a biasing member that biases the contact surface ofthe brake shoe away from the brake face of the brake drum.
 32. Thecomponent according to claim 29 wherein the brake face of the brake drumhas a cross-sectional shape in the form of a recessed trapezoidalconfiguration that constricts in width diametrically outward, andwherein the contact face of the brake shoe has a cross-sectional shapein the form of a convex trapezoidal configuration that constricts inwidth diametrically outward.
 33. The component according to claim 29wherein the brake drum comprises: a cylindrical drum body having thebrake face on an inner peripheral surface thereof; and a cooling disksecured to an outer periphery of the drum body.
 34. A bicycle hub brakecomponent for braking a hub of a wheel mounted on a bicycle frame,wherein the component comprises: a fixing bracket adapted to benonrotatably mounted to the bicycle frame; a brake drum adapted torotate integrally with the hub, wherein the brake drum has a brake faceon an inner peripheral surface thereof; a plurality of brake shoesdisposed peripherally around and diametrically inward of the brake faceof the brake drum, wherein the plurality of brake shoes are mounted tobe substantially nonrotatable relative to the fixing bracket; whereineach brake shoe has a contact surface that contacts the brake face ofthe brake drum to apply a braking force to the brake drum; wherein eachbrake shoe has an inclined surface formed in an upstream end of thecontact surface in a rotation direction of the brake drum such that theinclined surface forms an acute angle with a tangent to the contactsurface; a biasing member that biases the plurality of brake shoesdiametrically inward; an actuating arm that is rotatable around an axisof the hub; a cam member the rotates integrally with the actuating arm,wherein the cam member has a contoured outer peripheral surface; and aplurality of rollers disposed between the outer peripheral surface ofthe cam member and the plurality of brake shoes, wherein the pluralityof rollers move diametrically outward in response to rotation of the cammember to move the plurality of brake shoes diametrically outward. 35.The component according to claim 34 wherein the inclined surface of eachbrake shoe faces an axial side of the brake drum.
 36. The componentaccording to claim 34 wherein the brake face includes a grease-filledannular grease groove extending diametrically outwardly.
 37. Thecomponent according to claim 34 wherein the brake drum comprises: acylindrical drum body having the brake face on an inner peripheralsurface thereof; and a cooling disk secured to an outer periphery of thedrum body.